Mobile device/station position may be estimated from data gathered and processed from various systems. One positioning system in use by some mobile devices is the global navigation satellite system (GNSS). Mobile devices may also utilize terrestrial wireless communications systems, such as WiFi access points or Cell towers/base transceiver stations (BTS).
A position estimate, which may also be referred to as a position “fix”, for a mobile device may be obtained based at least in part on distances or ranges from the mobile device to transmitters or emitters, and also based at least in part on the locations of the one or more transmitters. The transmitters may comprise satellites in the case of GNSS, and/or terrestrial wireless transmitters (e.g., BTSs) in the case of a cellular communications system, for example. The locations of the wireless transmitters may be ascertained, in at least some cases, from information provided by the wireless transmitters themselves and/or from information stored in assistance data, for example.
With regard to device position determination from BTSs however, some BTS systems may not be adequately maintained (e.g., unstable clocks) or may be infrequently updated to provide accurate mobile device positioning. For example, BTS maintenance engineers may focus on voice or data throughput or reliability, with little to no emphasis on maintenance or optimization for mobile device positioning. Some problems when using BTSs for positioning may be more pronounced in areas where the BTS infrastructure is sparse or not fully developed. Therefore, discovery of misconfigured or unreliable BTSs may typically occur, if errors are detected at all, after mobile device user complaints are received by a cellular carrier or device manufacturer. BTS positioning errors may persist long after their first occurrence.